Colley-Urquhart submitted a letter of resignation to the board Tuesday.

"Though this resignation comes as a surprise, we would like to thank Coun. Colley-Urquhart for 10 years of service to the Commission," Thiessen said in an emailed statement. He was unavailable for comment Tuesday.

"Coun.Colley-Urquhart brought significant expertise and a passion for public safety. We valued her perspective and contribution and wish her the best of luck."

Mayor Naheed Nenshi said he was disappointed.

"The circumstances around this are certainly sad," he said. "But I know she feels strongly about standing up for the safety of everyone who wears the Calgary police uniform and certainly I feel strongly about that as well."

The commission earlier said it received two formal complaints regarding Colley-Urquhart's behaviour and was compelled to investigate.

Colley-Urquhart denies violations

In an earlier written statement, Thiessen said he addressed the allegations raised in the formal complaints directly with Colley-Urquhart.

"In our discussion, and in a written memo, I outlined the allegations presented by the complainants. Although Coun. Colley-Urquhart maintains that a breach of the code did not occur, our conversation gave me confidence that she strives to conduct herself in a way that balances the best interests of the Commission, the police service, the city, and her constituents," he wrote.

"The commission and Coun. Colley-Urquhart agreed that this informal resolution was the most appropriate remedy."

Thiessen determined there were four areas of the code of conduct Colley-Urquhart might have violated: speaking for the commission without express authority or delegation; using the position of a commissioner to advance personal interests; executing duties loyally, faithfully and impartially; and executing duties in accordance with applicable legislation.

Going public on alleged bullying

Colley-Urquhart went public with her concerns over the treatment of women in the force after she said she had dozens of private meetings with female officers who alleged they were bullied and harassed.

She said those officers approached her over frustration with the way a damning internal workplace review — which outlined many issues of bullying, harassment, intimidation and retaliation — was handled.

One of those women publicly resigned from the force at a Police Commission meeting at the beginning of February.

Coun. Ward Sutherland, who also sits on the commission, said he would not have aired the allegations in public and would have "brought it into the house where it belongs."

He also said a number of his council colleagues approached him upset with Colley-Urquhart's behaviour.

The balancing act

Mayor Naheed Nenshi said councillors are always playing a balancing act, determining which is the best route for achieving the public good.

"You've just got to make a decision every time of just, 'is bringing this thing out into the press doing more harm than good? Is having a public discussion a good thing to have?' It usually is, but again, it's a question that each councillor has to ask themselves," he said.

Nenshi said he hadn't looked at the letter from Thiessen in detail but he has "a lot of faith in the commission, in all the commission members, that they're going to do the right thing on this."